Re: Any non-biological complex systems?

Posted by Steve Smith on
URL: http://friam.383.s1.nabble.com/Any-non-biological-complex-systems-tp7589731p7589810.html

NST -

This is the kind of richness I trust you to always add to the conversation... a different (but similarly useful) splitting of hairs about language.   I realize that your broader use of the term "model" is fundamental and correct, and that the short-cut use of "model" for "mathematical model" has perhaps lead to sloppy thinking.  Or does it merely reflect it?   I suspect that many of us here do not have the practice or experience in using "model" in this larger sense well.

I suppose that the term "mathematical formalization of a model" might be most precise, but I think "mathematical model" is an acceptable contraction since I think "formalization" is implicit (redundant) when invoking "mathematical" in this sense.

I don't know if your (broader) definition of "model" would be more accurate if we prefixed it with "intuitive" or "mental" or even "metaphorical" model.

FWIW, when I talk with my daughter who is deeply embedded in the biosciences, they regularly use the shorthand of "model" to mean the invocation of a fairly formal analogy between one species and another.  e.g.   "a mouse model of xxx" or "a mosquito model of yyy", indicating that they do experimental studies on one species for various reasons (practical/ethical) to try to draw conclusions in another species.  I'm sure there is a very precise and elaborate practice involved.   I find the use of "model" very unnerving, possibly the same feeling you get when "simulants" use "model".  

Glen claims the title (appellation?) "simulant" which I find apt for *many* here who make their living (current or previous) by rendering mathematical models into computer simulations.  This task often requires thoughtfully choosing or developing the appropriate model TO render into code and place in the context of a series of experiments-by-simulation.   I am sometimes appalled at the lack of rigor brought to this whole process, but often the results are still useful for enhanced understanding if not rigorous advancement of the scientific domain they are exploring.

I believe that your contribution to the game theoretic model of human cooperation/defection known as "the iterated prisoner's dilemma" which we know as MOTH (My way Or The Highway) is a perfect example within the larger milieu.   I don't know what the higher level "model" the specific mathematical formulation we know as "prisoner's dilemma" defers to.

I myself have done a bit of this work but more often have been in a support role in trying to help "simulants" and the "modelers" they represent to develop more intuitive perspectives or understandings of the phenomena in question through a chain of analogical relations from the loosest of metaphor to the tightest of formal modeling.

In any case, I appreciate your asking of these questions.

And to your specific question of "is a Hurricane a Complex System", I think SG's answer was very good and hopefully helped to disambiguate the common use of "Complex System" in this forum.

Carry on,
- SS

On 5/28/17 11:10 PM, Stephen Guerin wrote:

 Nick asks:

Is a hurricane a “complex system”? 

It depends. What is your metaphor (model) of a hurricane? 

If I wanted to understand how a hurricane forms, I might model dissipative structure formation in the presence of temperature and pressure gradients. I would call this a complex system.

If I needed to add a hurricane track simulation to our Simtable, for the purposes of how my customers would use it for emergency planning, it would probably be enough to model its track as a random walker biased by global winds and a curve parameter to represent the Coriolis effect. I would not call this a complex system.

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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com
FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove